Posted by **Constantine** on Thursday, April 18, 2013 at 3:45pm.

Hi Dr. Bob. Could you please take a look at the question below and my work? I'm not sure how to get the correct answer for this question. I would greatly appreciate your help!

How many of the following molecules are polar?

BrCl3

CS2

SiF4

SO3

A) 1

B) 2

C) 3

D) 4

E) 0

The correct answer for this question is A) which is 1. However I could not find a polar molecule among the ones given.

BrCl3: the molecule has a T-shaped molecular geometry which could make it polar, but the Br-Cl electronegativity difference is 0.2 which makes it a covalent bond.

CS2: the molecule has a linear geometry and the electronegativity difference between C and S is 0, so this one is not polar either.

SiF4: the molecule has a tetrahedral molecular geometry so even though the S-iF electronegativity large and the bond is polar covalent, the bonds cancel each other out.

SO3: the molecule has a trigonal planar molecular geometry so the S-O bonds cancel each other out.

Could you please let me know which molecule is polar and why?

- Chemistry - molecular polarity -
**DrBob222**, Thursday, April 18, 2013 at 10:00pm
Your reasoning is correct for SiF4, SO3 and CS2.

BrCl3 is the polar molecule. Did you draw the Lewis structure? I can't draw it on this forum but if you try you will note that there are 28 electrons. If you place them around the Br atom, you must have two lone pairs on the central atom. The T-shape should tell you it is polar; I like to compare electronic geometries.

- Chemistry - molecular polarity -
**Constantine**, Thursday, April 18, 2013 at 11:00pm
Thank you so much. I should've ignored the electronegativity factor.

## Answer This Question

## Related Questions

- Chemistry - electron configuration - Hello Dr.Bob. Could you please take a look ...
- Dr. Bob - Thank you kind sir for guiding my work on the last question. You gave ...
- Physics - I'm understanding most of this physics, but here is one last question ...
- Math - Please Help Check My Answer - Please help me with the following question...
- Physics - Which of the following is correct for the reflected ray if a light ray...
- Dr.Bob - about your post to a previous question - For that question by Josh on ...
- For Dr.Bob - You helped me with a question, but I got stuck/didn't get the ...
- chemistry - A 1.325 g sample of an unknown vapor occupies 386 mL at 114 celsius...
- Math - Can someone please help me to answer the following question? The question...
- ATTENTION WRITEACHER! - Thanks so much for your help on my english question. I ...

More Related Questions